01.03.13 9:45 AM ET

Downton Abbey is back.

For some, that’s incentive enough to tune in to the award-winning British period drama, which returns to PBS’s Masterpiece Classic on Sunday, Jan. 6, for another season of soapy intrigue with the Crawley clan and their servants. Other viewers, who like me were disappointed with last season, will take more convincing. They should take heart: Season 3 of Downton is a return to form for the show, recapturing the dazzling wit and sweeping romance of the now-classic first season.

I was intensely critical of Season 2 of Downton when it aired last year. The sophomore season lacked the deft plotting and nuance of the first year, to say nothing of the disastrous “Patrick Crawley” subplot or the miraculous recovery of paralyzed heir Matthew Crawley (Dan Stevens), who nearly leapt from his wheelchair to dance the foxtrot. Such miscues mired the show in histrionic soapiness, upsetting the delicate balance between domestic drama and social change. Downton, after all, functions best when it focuses on small moments—a missing snuffbox, a snow-swept proposal, a knock on a door—not over-the-top plot twists.

Which isn’t to say that Season 3 lacks surprises. Alternately humorous and heartbreaking, Downton’s stunning third season packs several narrative punches into PBS’s seven-week run. Hopes are dashed, losses mount, and the most bitter change comes uninvited to Downton Abbey. That’s to be expected in a serial like this one, where stasis is the enemy of the narrative. Creator Julian Fellowes appears to be aware that the characters must change and grow, and so must their circumstances.

Indeed, Downton’s central conceit, keenly felt this season, seems to be the collision between the traditional and the modern, between those attempting to remain entrenched in the past—such as Lord Grantham (Hugh Bonneville) and his ever-vigilant butler, Carson (Jim Carter)—and those looking toward the future. But change always comes at a price, and calamity has a way of forcing drama, after all.

Season 3 brings with it tragedy both economic and familial. It begins with the shocking news that Robert (Bonneville) has speculated unwisely and ruined the entailed fortune of his wife, Cora (Elizabeth McGovern), and quite possibly the family’s resources forever. The case against poor Mr. Bates (Brendan Coyle) seems even more impossible, despite the investigative prowess of his wife, Anna (Joanne Froggatt), who is grimly determined to prove his innocence.

But it’s not all doom and gloom for the residents of the manor house. The arrival of Cora’s wealthy American mother, Martha Levinson (Shirley MacLaine), brings with it the possibility both of new investment and renewed enmity with the Dowager Countess, Violet (Dame Maggie Smith). Their scenes together crackle; theirs is a battle of wicked wits between two women who have seen it all. MacLaine appears only in the first two episodes of the season, but her presence at Downton is a jagged thorn among the English roses, sisters Mary (Michelle Dockery), Edith (Laura Carmichael), and Sybil (Jessica Brown Findlay).

This season, Fellowes adds several new members to the show’s already sprawling cast, including new servants—handsome footman Jimmy (Edward Speleers), upwardly mobile Alfred (Matt Milne), and new kitchen maid Ivy (Cara Theobold), all of whom become enmeshed in a love quadrangle of sorts—and a bright young thing in Lady Rose MacClare (Lily James), the offspring of family relations who is destined to become a ward of the Crawleys. Rose’s inclusion is a wise move on Fellowes’s part; her arrival is an entryway to the cultural minefield of the 1920s: nightclubs, jazz, and the permissiveness and abandon of youth.

Elsewhere, former co-conspirators Miss O’Brien (Siobhan Finneran) and Thomas (Rob James-Collier), thick as thieves for the last two seasons, find themselves at war, and O’Brien’s revenge against Thomas—for mistreating her nephew Alfred, a former hotel waiter hired as a footman at her behest—is shockingly cruel, even for O’Brien. Daisy (Sophie McShera), continuing to chafe under the yoke of kitchen overseer Mrs. Patmore (Lesley Nicol), threatens a strike, and a personal matter brings Mrs. Patmore and Mrs. Hughes (Phyllis Logan) together.

It’s these small but pivotal moments that offer the most poignancy: the sight of Mrs. Hughes, as she shuts off the lights of the downstairs hallway, musing on mortality in the darkness. A veil cascading through a stairwell. A father standing at a window. There is a deep sense this season of the enormity of birth and death, the sense that we all get just one shot at life. Yet Fellowes once again deftly balances the weight of these contemplations against the everyday occurrences of life within the house. Who gets to carry in the fish tray versus the sauce to the dining room becomes just as important, in a way, as matters of survival.

While Downton’s subpar second season was salvaged by its superb Christmas Special, the third season seems to reverse that trend. The strength of Season 3 is marred somewhat by its relatively lackluster season finale (airing Stateside on Feb. 17), a deeply polarizing episode whose conclusion has already been spoiled by the press. Depicting two separate narratives—the Crawleys head to Duneagle Castle in Scotland, while most of their servants remain at Downton and attend a fair—the finale is filled with a sense of doom. Chekhov’s gun, perhaps represented best here by the shotguns packed by the doddering valet Mr. Molesley (Kevin Doyle), doesn’t quite go off as expected, however. Instead the season ends on a particularly maudlin and frustrating note, one that squanders the potential and promise of one of the season’s main plots, the modernization of Downton Abbey.

The spoilery reasons behind the plot twist—a deus ex machina in more than name—are now very public, but the potential damage done to the overarching narrative is undiminished. I’m intrigued to see just how the Crawley family reacts. Incidents such as this tend to lead to much drama down the line, but I’m also quite frustrated with how it was handled within the story itself. More satisfying ways of achieving this end (do notice how carefully I’m tiptoeing around what happens here) come to mind, particularly ones that better use the trip to Scotland for full effect.

But Downton, both the great house and the show itself, survive as they always have: with grace and dignity intact, one hopes. And despite my misgivings about how the twist was handled, I refuse to let the finale deter me from seeing Season 3 of Downton Abbey for what it is: a truly marvelous season of television that entrances, even as it breaks your heart.